mmc: Test bus-width for old MMC devices

Some old MMC devices fail with the 4/8 bits the driver tries to use
exclusively.  This patch adds a test for the given bus setup and falls
back to the lower bit mode (until 1-bit mode) when the test fails.

[Major rework and refactoring by tiwai]
[Quirk addition and many fixes by prakity]

Signed-off-by: Aries Lee <arieslee@jmicron.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Philip Rakity <prakity@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 3a85e73a38a9..bcb793ec7374 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -172,6 +172,7 @@ struct mmc_host {
 #define MMC_CAP_1_2V_DDR        (1 << 12)       /* can support */
                                                 /* DDR mode at 1.2V */
 #define MMC_CAP_POWER_OFF_CARD  (1 << 13)       /* Can power off after boot */
+#define MMC_CAP_BUS_WIDTH_TEST  (1 << 14)       /* CMD14/CMD19 bus width ok */
 
         mmc_pm_flag_t           pm_caps;        /* supported pm features */